In Arch Linux
mkinitcpio -p linux
shows
Possibly missing firmware for module: aic94xx
Possibly missing firmware for module: wd719x
git clone https://aur.archlinux.org/aic94xx-firmware.git
cd aic94xx-firmware
makepkg -sri
git clone https://aur.archlinux.org/wd719x-firmware.git
cd wd719x-firmware
makepkg -sri
and then mkinitcpio -p linux
again.
This seems the practical and applicable approach I have seen thus far suggested.
If this problem lingers much longer, which it seems it just might, I will be going down the C rabbit holes of interest to it in the near enough future, I might just have to deal with myself (or with whom ever else simply wants this very real issue corrected)
As I see it, warnings that can then be disabled, individually or perhaps collectively (though that's less optimal) would be a reasonable means of achieving the goals of those who have joined the chorus of irritated users while not excluding the ever shrinking group that would find these warnings helpful from receiving them and taking appropriate action.
Being that silencing output is a regular option affixed to many programs, I can't imagine finding some means of doing so outside of the scope of the programming that has generated them and would enhance the overall professional appearance of Arch Linux, which it seems is a common goal to all camps and a motivating factor on both sides of this spirited discussion.